Formation breaking assemblies, such as rock breakers, are often used to break hard materials such as rocks, cement, or other hard materials. These assemblies often comprise a steel shaft with an end adapted to contact the formation. These formation breaking assemblies are often mounted to a vehicle or are some times permanently installed in quarries where rocks are brought to the breaking assembly.
U.S. Pat. No. 5,944,117 to Burkholder et al., which is herein incorporated by reference for all that it contains, discloses an improved fluid actuated percussive impact tool of the valveless type adapted for down hole drilling. The impact tool includes a casing, a back head, a distributor located at a first end of the casing, and an impact receiving device located at a second end of the casing. A chamber is located between the distributor and the impact receiving device. A cylinder sleeve is located in the chamber adjacent to the distributor. A first pressurized fluid passage is located between the casing and the cylinder sleeve for passing pressurized fluid from the distributor to the chamber. A piston is located in the chamber for reciprocating axial movement. Axially extending ports are located on at least one of the piston, the cylinder sleeve and the casing in the chamber for alternately supplying pressurized fluid to upper and lower chamber portions. An exhaust bore is provided in fluid communication with the chamber which selectively exhausts pressurized fluid from the upper and lower chamber portions to thereby reciprocate the piston between a first position wherein the first end of the piston is in contact with the impact receiving device and a second position wherein the second end is in proximity to the distributor to impart blows on the impact receiving device. The piston has an elongated generally cylindrical body and a reduced diameter neck forming a first lifting surface which is offset a first distance from the first end of the piston. A first axially extending port is located on the piston between the first and second sealing surfaces. The intersection of the first sealing surface and the first axially extending port defines a port opening timing location located a second distance from the first end of the piston. The first distance on the impact receiving device is at least 40% of second distance such that the frequency of blows per minute is increased by at least 10 percent.
U.S. Pat. No. 6,857,482 to Comarmond, which is herein incorporated by reference for all that it contains, discloses an apparatus comprising a body wherein a piston is mounted sliding alternately driven by an incompressible fluid under pressure, said body containing part of a tool which is guided in translation in a wear sleeve, the end of the tool located inside the body being subjected to the repeated impacts of the piston, while the other end projects beyond the body and is designed to be supported on the rock or analogue to be destroyed, the tool being retained in the body by at least a transverse key. One of the keys retaining the tool passes through aligned holes provided in the body, into the wear sleeve, and overlaps inside the inner cylindrical space of the sleeve, the tool having a transverse groove for the key to pass through.
U.S. Pat. No. 4,759,412 to Brazell, II, which is herein incorporated by reference for all that it contains, discloses a rock breaking device adapted to be coupled to the lifting arms of a tractor or similar vehicle is disclosed, the device having an upstanding guide tube with a hammer, chisel, and anvil disposed therein. The hammer can be raised within the guide tube by frictional engagement with a drive member and is then allowed to fall by gravitational force to impact the chisel and/or the chisel and anvil, thereby driving the chisel into the surface to be broken. The device has a shock absorber to minimize the force of impact and as a safety feature, cannot be made operational until actually positioned on the surface to be broken.
U.S. Pat. No. 4,470,440 to Thor, which is herein incorporated by reference for that it contains, discloses an impact producing tool that has a longitudinal axis with an impacting working head member rigidly connected to the end of a housing. An elongated handle is floatingly connected to and extends from the impacting head member and out of an opening disposed an end cap portion at the other end of the housing. A positioning member is located on the impacting head member and has a structural configuration effective to maintain the elongated handle at a predetermined position with respect to the impacting working head member. A hammer element is movably disposed on the elongated handle and is effective to apply a striking force on the impact receiving end of the housing. The impacting working head member has a structural configuration effective to act on a workpiece or work surface when the striking force is applied to the impact receiving end of the housing. The floating connection between the elongated handle and the housing overcomes a basic problem of structural deficiencies associated with handles rigidly connected to a housing element. A particular feature of the invention is the interchangeability of working head members which accomplish various functions with respect to the impact producing tool.